BACKGROUND Extracorporeal membrane oxygenation(ECMO)is a new type of extracorporeal respiratory and circulatory assistance device.It can drain venous blood out of the body and inject it into veins or arteries after be...BACKGROUND Extracorporeal membrane oxygenation(ECMO)is a new type of extracorporeal respiratory and circulatory assistance device.It can drain venous blood out of the body and inject it into veins or arteries after being oxygenated by an oxygenator(membrane lung)to replace lung and heart functions in a short time.ECMO can provide tissue blood perfusion and gas exchange almost equivalent to cardiac output and extend the effective treatment time window for patients with acute circulatory failure to restore cardiopulmonary function.CASE SUMMARY We report a case of an 81-year-old woman who underwent whole cerebral angiography,basilar artery thrombectomy and stent thrombectomy in the posterior artery of the left brain after implantation of ECMO.The patient was admitted to the hospital due to myocardial infarction.Considering that the cause of the patient’s disturbance of consciousness was unknown and cerebrovascular accident could not be ruled out after the implantation of ECMO,the department of Radioactive Intervention performed cerebral angiography.And the result of the angiography indicated vascular occlusion.After the basilar artery thrombectomy and stent thrombectomy in the posterior artery of the left brain,the patency of the occlusive vessel was achieved.CONCLUSION Although the patient eventually died of circulatory failure,the result of this case verifies the feasibility of cerebral angiography and thrombectomy in patients with implanted ECMO in the intubated state.展开更多
In this study,a common-node DEM-SPH coupling model based on the shared node method is proposed,and a fluid–structure coupling method using the common-node discrete element method-smoothed particle hydrodynamics(DS-SP...In this study,a common-node DEM-SPH coupling model based on the shared node method is proposed,and a fluid–structure coupling method using the common-node discrete element method-smoothed particle hydrodynamics(DS-SPH)method is developed using LS-DYNA software.The DEM and SPH are established on the same node to create common-node DEM-SPH particles,allowing for fluid–structure interactions.Numerical simulations of various scenarios,including water entry of a rigid sphere,dam-break propagation over wet beds,impact on an ice plate floating on water and ice accumulation on offshore structures,are conducted.The interaction between DS particles and SPH fluid and the crack generation mechanism and expansion characteristics of the ice plate under the interaction of structure and fluid are also studied.The results are compared with available data to verify the proposed coupling method.Notably,the simulation results demonstrated that controlling the cutoff pressure of internal SPH particles could effectively control particle splashing during ice crushing failure.展开更多
In the present study,the nanofliud natural convection is investigated by the energy-conserving dissipative particle dynamics(eDPD)method,where the nanoparticles are considered at the single-particle level.The thermal ...In the present study,the nanofliud natural convection is investigated by the energy-conserving dissipative particle dynamics(eDPD)method,where the nanoparticles are considered at the single-particle level.The thermal expansion coefficientβand the viscosityμof the simulated system containing nanoparticles are calculated and found to be in close alignment with the previous simulation results.The single-particle hydrodynamics in e DPD enables simulations of nanofluid natural convection with higher Rayleigh numbers and greater nanoparticle volume fractions.Additionally,this approach is utilized to simulate the nanoparticle distribution during the enhanced heat transfer process in the nanofluid natural convection.The localized aggregation of nanoparticles enhances the heat transfer performance of the nanofluid under specific Rayleigh numbers and nanoparticles volume fractions.展开更多
Residual strength is an indispensable factor in evaluating rock fracture,yet the current Smoothed Particle Hydrodynamics(SPH)framework rarely considers its influence when simulating fracture.An improved cracking strat...Residual strength is an indispensable factor in evaluating rock fracture,yet the current Smoothed Particle Hydrodynamics(SPH)framework rarely considers its influence when simulating fracture.An improved cracking strategy considering residual stress in the base bond SPH method was proposed to simulate failures in layered rocks and slopes and verified by experimental results and other simulation methods(i.e.,the discrete element method).Modified Mohr–Coulomb failure criterion was applied to distinguish the mixed failure of tensile and shear.Bond fracture markψwas introduced to improve the kernel function after tensile damage,and the calculation of residual stress after the damage was derived after shear damage.Numerical simulations were carried out to evaluate its performance under different stress and scale conditions and to verify its effectiveness in realistically reproducing crack initiation and propagation and coalescence,even fracture and separation.The results indicate that the improved cracking strategy precisely captures the fracture and failure pattern in layered rocks and rock slopes.The residual stress of brittle tock is correctly captured by the improved SPH method.The improved SPH method that considers residual strength shows an approximately 13%improvement in accuracy for the safety factor of anti-dip layered slopes compared to the method that does not consider residual strength,as validated against analytical solutions.We infer that the improved SPH method is effective and shows promise for applications to continuous and discontinuous rock masses.展开更多
A fluid-structure interaction approach is proposed in this paper based onNon-Ordinary State-Based Peridynamics(NOSB-PD)and Updated Lagrangian Particle Hydrodynamics(ULPH)to simulate the fluid-structure interaction pro...A fluid-structure interaction approach is proposed in this paper based onNon-Ordinary State-Based Peridynamics(NOSB-PD)and Updated Lagrangian Particle Hydrodynamics(ULPH)to simulate the fluid-structure interaction problem with large geometric deformation and material failure and solve the fluid-structure interaction problem of Newtonian fluid.In the coupled framework,the NOSB-PD theory describes the deformation and fracture of the solid material structure.ULPH is applied to describe the flow of Newtonian fluids due to its advantages in computational accuracy.The framework utilizes the advantages of NOSB-PD theory for solving discontinuous problems and ULPH theory for solving fluid problems,with good computational stability and robustness.A fluidstructure coupling algorithm using pressure as the transmission medium is established to deal with the fluidstructure interface.The dynamic model of solid structure and the PD-ULPH fluid-structure interaction model involving large deformation are verified by numerical simulations.The results agree with the analytical solution,the available experimental data,and other numerical results.Thus,the accuracy and effectiveness of the proposed method in solving the fluid-structure interaction problem are demonstrated.The fluid-structure interactionmodel based on ULPH and NOSB-PD established in this paper provides a new idea for the numerical solution of fluidstructure interaction and a promising approach for engineering design and experimental prediction.展开更多
Predicting the response of liquefied natural gas(LNG)contained in vessels subjected to external waves is extremely important to ensure the safety of the transportation process.In this study,the coupled behavior due to...Predicting the response of liquefied natural gas(LNG)contained in vessels subjected to external waves is extremely important to ensure the safety of the transportation process.In this study,the coupled behavior due to ship motion and liquid tank sloshing has been simulated by the Smoothed-Particle Hydrodynamics(SPH)method.Firstly,the sloshing flow in a rectangular tank was simulated and the related loads were analyzed to verify and validate the accuracy of the present SPH solver.Then,a three-dimensional simplified LNG carrier model,including two prismatic liquid tanks and a wave tank,was introduced.Different conditions were examined corresponding to different wave lengths,wave heights,wave heading angles,and tank loading rates.Finally,the effects of liquid tank loading rate on LNG ship motions and sloshing loading were analyzed,thereby showing that the SPH method can effectively provide useful indications for the design of liquid cargo ships.展开更多
Natural convection is a heat transfer mechanism driven by temperature or density differences,leading to fluid motion without external influence.It occurs in various natural and engineering phenomena,influencing heat t...Natural convection is a heat transfer mechanism driven by temperature or density differences,leading to fluid motion without external influence.It occurs in various natural and engineering phenomena,influencing heat transfer,climate,and fluid mixing in industrial processes.This work aims to use the Updated Lagrangian Particle Hydrodynamics(ULPH)theory to address natural convection problems.The Navier-Stokes equation is discretized using second-order nonlocal differential operators,allowing a direct solution of the Laplace operator for temperature in the energy equation.Various numerical simulations,including cases such as natural convection in square cavities and two concentric cylinders,were conducted to validate the reliability of the model.The results demonstrate that the proposed model exhibits excellent accuracy and performance,providing a promising and effective numerical approach for natural convection problems.展开更多
The Theory of General Singularity is presented, unifying quantum field theory, general relativity, and the standard model. This theory posits phonons as fundamental excitations in a quantum vacuum, modeled as a Bose-E...The Theory of General Singularity is presented, unifying quantum field theory, general relativity, and the standard model. This theory posits phonons as fundamental excitations in a quantum vacuum, modeled as a Bose-Einstein condensate. Through key equations, the role of phonons as intermediaries between matter, energy, and spacetime geometry is demonstrated. The theory expands Einsteins field equations to differentiate between visible and dark matter, and revises the standard model by incorporating phonons. It addresses dark matter, dark energy, gravity, and phase transitions, while making testable predictions. The theory proposes that singularities, the essence of particles and black holes, are quantum entities ubiquitous in nature, constituting the very essence of elementary particles, seen as micro black holes or quantum fractal structures of spacetime. As the theory is refined with increasing mathematical rigor, it builds upon the foundation of initial physical intuition, connecting the spacetime continuum of general relativity with the hydrodynamics of the quantum vacuum. Inspired by the insights of Tesla and Majorana, who believed that physical intuition justifies the infringement of mathematical rigor in the early stages of theory development, this work aims to advance the understanding of the fundamental laws of the universe and the perception of reality.展开更多
Viscoelastic flows play an important role in numerous engineering fields,and the multiscale algorithms for simulating viscoelastic flows have received significant attention in order to deepen our understanding of the ...Viscoelastic flows play an important role in numerous engineering fields,and the multiscale algorithms for simulating viscoelastic flows have received significant attention in order to deepen our understanding of the nonlinear dynamic behaviors of viscoelastic fluids.However,traditional grid-based multiscale methods are confined to simple viscoelastic flows with short relaxation time,and there is a lack of uniform multiscale scheme available for coupling different solvers in the simulations of viscoelastic fluids.In this paper,a universal multiscale method coupling an improved smoothed particle hydrodynamics(SPH)and multiscale universal interface(MUI)library is presented for viscoelastic flows.The proposed multiscale method builds on an improved SPH method and leverages the MUI library to facilitate the exchange of information among different solvers in the overlapping domain.We test the capability and flexibility of the presented multiscale method to deal with complex viscoelastic flows by solving different multiscale problems of viscoelastic flows.In the first example,the simulation of a viscoelastic Poiseuille flow is carried out by two coupled improved SPH methods with different spatial resolutions.The effects of exchanging different physical quantities on the numerical results in both the upper and lower domains are also investigated as well as the absolute errors in the overlapping domain.In the second example,the complex Wannier flow with different Weissenberg numbers is further simulated by two improved SPH methods and coupling the improved SPH method and the dissipative particle dynamics(DPD)method.The numerical results show that the physical quantities for viscoelastic flows obtained by the presented multiscale method are in consistence with those obtained by a single solver in the overlapping domain.Moreover,transferring different physical quantities has an important effect on the numerical results.展开更多
We have recently proposed a new technique of plasma tailoring by laser-driven hydrodynamic shockwaves generated on both sides of a gas jet[Marquès et al.,Phys.Plasmas 28,023103(2021)].In a continuation of this nu...We have recently proposed a new technique of plasma tailoring by laser-driven hydrodynamic shockwaves generated on both sides of a gas jet[Marquès et al.,Phys.Plasmas 28,023103(2021)].In a continuation of this numerical work,we study experimentally the influence of the tailoring on proton acceleration driven by a high-intensity picosecond laser in three cases:without tailoring,by tailoring only the entrance side of the picosecond laser,and by tailoring both sides of the gas jet.Without tailoring,the acceleration is transverse to the laser axis,with a low-energy exponential spectrum,produced by Coulomb explosion.When the front side of the gas jet is tailored,a forward acceleration appears,which is significantly enhanced when both the front and back sides of the plasma are tailored.This forward acceleration produces higher-energy protons,with a peaked spectrum,and is in good agreement with the mechanism of collisionless shock acceleration(CSA).The spatiotemporal evolution of the plasma profile is characterized by optical shadowgraphy of a probe beam.The refraction and absorption of this beam are simulated by post-processing 3D hydrodynamic simulations of the plasma tailoring.Comparison with the experimental results allows estimation of the thickness and near-critical density of the plasma slab produced by tailoring both sides of the gas jet.These parameters are in good agreement with those required for CSA.展开更多
To adapt to the change of aquaculture workshop site,optimize the shape of aquaculture tanks and improve the utilization rate of breeding space,it is necessary to determine the appropriate length width ratio parameters...To adapt to the change of aquaculture workshop site,optimize the shape of aquaculture tanks and improve the utilization rate of breeding space,it is necessary to determine the appropriate length width ratio parameters of aquaculture tanks.In this paper,computational fluid dynamics(CFD)technology is adopted to study the flow field performance of aquaculture tanks with different L/B ratios(L:the length;B:the width,of aquaculture tank)and different jet direction conditions(lengthways jet and widthways jet).A three-dimensional numerical calculation model of turbulence in rounded rectangle aquaculture tanks in dual-diagonal-inlet layout was established.Jet directions are arranged lengthways and widthways,and the water flow velocity,resistance coefficient change,vorticity,etc.are analyzed under two working conditions.Results show that the flow field performance in aquaculture tank decreases with the increase of the L/B ratio.The flow field performed well when L/B was 1.0-1.3,sharply dropped at 1.4-1.6,and poor at 1.7-1.9.The results provided a theoretical basis for the design and optimization in flow field performance of the industrialized circulating aquaculture tanks.展开更多
Two-dimensional(2D)flume experiments are useful in investigating the performances of floating breakwaters(FBs),including hydrodynamic performances,motion responses,and mooring forces.Designing a reasonable gap between...Two-dimensional(2D)flume experiments are useful in investigating the performances of floating breakwaters(FBs),including hydrodynamic performances,motion responses,and mooring forces.Designing a reasonable gap between the flume wall and the FBs is a critical step in 2D flume tests.However,research on the effect of the gap on the accuracy of 2D FB experimental results is scarce.To address this issue,a numerical wave tank is developed using CFD to estimate the wave-FB interaction of a moored dual-cylindrical FB,and the results are compared to experimental data from a previously published work.There is good agreement between them,indicating that the numerical model is sufficiently accurate.The numerical model is then applied to explore the effect of gap diffraction on the performance of FBs in2D experiments.It was discovered that the nondimensional gap length L_(Gap)/W_(Pool)should be smaller than 7.5%to ensure that the relative error of the transmission coefficient is smaller than 3%.The influence of the gap is also related to the entering wave properties,such as the wave height and period.展开更多
It is of vital significance to investigate mass transfer enhancements for chemical engineering processes.This work focuses on investigating the coupling influence of embedding wire mesh and adding solid particles on b...It is of vital significance to investigate mass transfer enhancements for chemical engineering processes.This work focuses on investigating the coupling influence of embedding wire mesh and adding solid particles on bubble motion and gas-liquid mass transfer process in a bubble column.Particle image velocimetry(PIV)technology was employed to analyze the flow field and bubble motion behavior,and dynamic oxygen absorption technology was used to measure the gas-liquid volumetric mass transfer coefficient(kLa).The effect of embedding wire mesh,adding solid particles,and wire mesh coupling solid particles on the flow characteristic and kLa were analyzed and compared.The results show that the gas-liquid interface area increases by 33%-72%when using the wire mesh coupling solid particles strategy compared to the gas-liquid two-phase flow,which is superior to the other two strengthening methods.Compared with the system without reinforcement,kLa in the bubble column increased by 0.5-1.8 times with wire mesh coupling solid particles method,which is higher than the sum of kLa increases with inserting wire mesh and adding particles,and the coupling reinforcement mechanism for affecting gas-liquid mass transfer process was discussed to provide a new idea for enhancing gas-liquid mass transfer.展开更多
Artificial fish reef is a kind of artificial structure in water,which provides a necessary and safe place for aquatic life such as fish to inhabit,grow,and breed,and creates an environment suitable for fish growth,so ...Artificial fish reef is a kind of artificial structure in water,which provides a necessary and safe place for aquatic life such as fish to inhabit,grow,and breed,and creates an environment suitable for fish growth,so as to protect and multiply fishery resources.In a large time scale,the physical process of sea area can deeply affect the chemical process and biological process,so the structure characteristics of artificial reef are the key factors affecting the flow field effect around the reef.In this study,through the hydrodynamic experiments of four kinds of reef models,including big windows box reef,big and small windows box reef,"(卐)"shaped reef and double-layer shellfish breeding reef,the influence of single reef structure on the flow field effect is analyzed,and the force conditions of different reefs under the same incoming current velocity are obtained.According to the simulation results,the safety research and calculation of five kinds of reef models are carried out,and the volumes of vortex area and upwelling area behind four kinds of reef are obtained.Using hydrodynamic model to simulate the flow field effect of reef area,optimizing the reef structure design,improving the maximum biological trapping and proliferation effect of reef,can provide theoretical guidance and scientific and technological support for the construction of reef area.展开更多
BACKGROUND The inferior vena cava filter is utilized worldwide to intercept thrombi and to reduce the risk of fatal pulmonary embolism(PE).However,filter-related thrombosis is a complication of filter implantation.End...BACKGROUND The inferior vena cava filter is utilized worldwide to intercept thrombi and to reduce the risk of fatal pulmonary embolism(PE).However,filter-related thrombosis is a complication of filter implantation.Endovascular methods such as AngioJet rheolytic thrombectomy(ART)and catheter-directed thrombolysis(CDT)can treat filter-related caval thrombosis,but the clinical outcomes of both treatment modalities have not been determined.AIM To compare the treatment outcomes of AngioJet rheolytic thrombectomy vs catheter-directed thrombolysis in patients with filter-related caval thrombosis.METHODS In this single-center retrospective study,65 patients(34 males and 31 females;mean age:59.0±13.43 years)with intrafilter and inferior vena cava thrombosis were enrolled between January 2021 and August 2022.These patients were assigned to either the AngioJet group(n=44)or the CDT group(n=21).Clinical data and imaging information were collected.Evaluation measures included thrombus clearance rate,periprocedural complications,urokinase dosage,incidence of PE,limb circumference difference,length of stay,and filter removal rate.RESULTS Technical success rates were 100%in the AngioJet and CDT groups.In the AngioJet group,grade II and grade III thrombus clearance was achieved in 26(59.09%)and 14(31.82%)patients,respectively.In the CDT group,grade II and grade III thrombus clearance was accomplished in 11(52.38%)patients and 8(38.10%)patients,respectively(P>0.05).The peridiameter difference of the thigh was significantly reduced in patients from both groups after treatment(P<0.05).The median dosage of urokinase was 0.08(0.02,0.25)million U in the AngioJet group and 1.50(1.17,1.83)million U in the CDT group(P<0.05).Minor bleeding was shown in 4(19.05%)patients in the CDT group,and when it was compared with that in the AngioJet group,the difference was statistically significant(P<0.05).No major bleeding occurred.Seven(15.91%)patients in the AngioJet group had hemoglobinuria and 1(4.76%)patient in the CDT group had bacteremia.There were 8(18.18%)patients with PE in the AngioJet group and 4(19.05%)patients in the CDT group before the intervention(P>0.05).Computed tomography angiopulmonography(CTA)showed that PE was resolved after the intervention.New PE occurred in 4(9.09%)patients in the AngioJet group and in 2(9.52%)patients in the CDT group after theintervention(P>0.05).These cases of PE were asymptomatic.The mean length of stay was longer in the CDT group(11.67±5.34 d)than in the AngioJet group(10.64±3.52 d)(P<0.05).The filter was successfully retrieved in the first phase in 10(47.62%)patients in the CDT group and in 15(34.09%)patients in the AngioJet group(P>0.05).Cumulative removal was accomplished in 17(80.95%)out of 21 patients in the CDT group and in 42(95.45%)out of 44 patients in the ART group(P>0.05).The median indwelling time for patients with successful retrieval was 16(13139)d in the CDT group and 59(12231)d in the ART group(P>0.05).CONCLUSION Compared with catheter-directed thrombolysis,AngioJet rheolytic thrombectomy can achieve similar thrombus clearance effects,improve the filter retrieval rate,reduce the urokinase dosage and lower the risk of bleeding events in patients with filter-related caval thrombosis.展开更多
Objective: To evaluate the risk factors for hemoglobinuria and acute kidney injury(AKI) after percutaneous mechanical thrombectomy(MT) with or without catheter-directed thrombolysis(CDT) for iliofemoral deep vein thro...Objective: To evaluate the risk factors for hemoglobinuria and acute kidney injury(AKI) after percutaneous mechanical thrombectomy(MT) with or without catheter-directed thrombolysis(CDT) for iliofemoral deep vein thrombosis(IFDVT).Methods: Patients with IFDVT who had MT with the Angio Jet catheter(group A), MT plus CDT(group B), or CDT alone(group C) from January 2016 to March 2020 were retrospectively evaluated. Hemoglobinuria was monitored throughout the treatment course, and postoperative AKI was assessed by comparing the preoperative(baseline) and postoperative serum creatinine(sCr) levels from the electronic medical records of all patients. AKI was defined as an elevation in the sCr level exceeding 26.5 μmol/L within 72 h after the operation according to the Kidney Disease Improving Global Outcomes criteria.Results: A total of 493 consecutive patients with IFDVT were reviewed, of which 382(mean age, 56 ± 11 years;41% of them were females;97 in group A, 128 in group B, and 157 in group C) were finally analyzed. Macroscopic hemoglobinuria was evident in 44.89% of the patients of the MT groups(101/225, 39 in group A, and 62 in group B), with no significant difference between the groups(P = 0.219), but not in the patients in group C. None of the patients developed AKI(mean sCr difference-2.76 ± 13.80 μmol/L, range =-80.20 to 20.60 μmol/L) within 72h after surgery.Conclusions: Rheolytic MT is an independent risk factor for hemoglobinuria. A proper aspiration strategy, hydration, and alkalization following thrombectomy are particularly favorable for preventing AKI.展开更多
BACKGROUND A carotid-cavernous fistula(CCF)is an abnormal connection between the internal carotid artery(ICA)and the cavernous sinus.Although direct CCFs typically result from trauma or as an iatrogenic complication o...BACKGROUND A carotid-cavernous fistula(CCF)is an abnormal connection between the internal carotid artery(ICA)and the cavernous sinus.Although direct CCFs typically result from trauma or as an iatrogenic complication of neuroendovascular procedures,they can occur as surgery-related complications after mechanical thrombectomy(MT).With the widespread use of MT in patients with acute ischemic stroke complicated with large vessel occlusion,it is important to document CCF following MT and how to avoid them.In this study,we present a case of a patient who developed a CCF following MT and describe in detail the characteristics of ICA tortuosity in this case.CASE SUMMARY A 60-year-old woman experienced weakness in the left upper and lower limbs as well as difficulty speaking for 4 h.The neurological examination revealed left central facial paralysis and left hemiplegia,with a National Institutes of Health Stroke Scale score of 9.Head magnetic resonance imaging revealed an acute cerebral infarction in the right basal ganglia and radial crown.Magnetic resonance angiography demonstrated an occlusion of the right ICA and middle cerebral artery.Digital subtraction angiography demonstrated distal occlusion of the cervical segment of the right ICA.We performed suction combined with stent thrombectomy.Then,postoperative angiography was performed,which showed a right CCF.One month later,CCF embolization was performed,and the patient’s clinical symptoms have significantly improved 5 mo after the operation.CONCLUSION Although a CCF is a rare complication after MT,it should be considered.Understanding the tortuosity of the internal carotid-cavernous sinus may help predict the complexity of MT and avoid this complication.展开更多
Flow-type landslide is one type of landslide that generally exhibits characteristics of high flow velocities,long jump distances,and poor predictability.Simulation of its propagation process can provide solutions for ...Flow-type landslide is one type of landslide that generally exhibits characteristics of high flow velocities,long jump distances,and poor predictability.Simulation of its propagation process can provide solutions for risk assessment and mitigation design.The smoothed particle hydrodynamics(SPH)method has been successfully applied to the simulation of two-dimensional(2D)and three-dimensional(3D)flow-like landslides.However,the influence of boundary resistance on the whole process of landslide failure is rarely discussed.In this study,a boundary condition considering friction is proposed and integrated into the SPH method,and its accuracy is verified.Moreover,the Navier-Stokes equation combined with the non-Newtonian fluid rheologymodel was utilized to solve the dynamic behavior of the flow-like landslide.To verify its performance,the Shuicheng landslide event,which occurred in Guizhou,China,was taken as a case study.In the 2D simulation,a sensitivity analysis was conducted,and the results showed that the shearing strength parameters have more influence on the computation accuracy than the coefficient of viscosity.Afterwards,the dynamic characteristics of the landslide,such as the velocity and the impact area,were analyzed in the 3D simulation.The simulation results are in good agreement with the field investigations.The simulation results demonstrate that the SPH method performs well in reproducing the landslide process,and facilitates the analysis of landslide characteristics as well as the affected areas,which provides a scientific basis for conducting the risk assessment and disaster mitigation design.展开更多
Acute ischemic stroke is one of the common discases in Chinese,among which acute ischemic stroke with large vessel occlusion(AIS-LVO)has thc most serious complications and has the risk of death.Studies have shown that...Acute ischemic stroke is one of the common discases in Chinese,among which acute ischemic stroke with large vessel occlusion(AIS-LVO)has thc most serious complications and has the risk of death.Studies have shown that reperfusion is a first-line treatment for the effective rescue of ischemic brain tissue,usually mainly by mechanical|hrombectomy(MT),supplemented by intravenous thrombolysis.However,there are still complications after large blood vessel occlusion and MT.such as blecding and infection at the puncture point,vasospasm,vascular dissection,subarachnoid hemorrhage,hcmonhagic transfomation,reembolization,and massive cerebral infarction,ctc.The high risk factors and corresponding measures of complications after MT by revicwing the rescarch analysis.展开更多
In classical smoothed particle hydrodynamics(SPH)fluid simulation approaches,the smoothing length of Lagrangian particles is typically constant.One major disadvantage is the lack of adaptiveness,which may compromise a...In classical smoothed particle hydrodynamics(SPH)fluid simulation approaches,the smoothing length of Lagrangian particles is typically constant.One major disadvantage is the lack of adaptiveness,which may compromise accuracy in fluid regions such as splashes and surfaces.Attempts to address this problem used variable smoothing lengths.Yet the existing methods are computationally complex and non-efficient,because the smoothing length is typically calculated using iterative optimization.Here,we propose an efficient non-iterative SPH fluid simulation method with variable smoothing length(VSLSPH).VSLSPH correlates the smoothing length to the density change,and adaptively adjusts the smoothing length of particles with high accuracy and low computational cost,enabling large time steps.Our experimental results demonstrate the advantages of the VSLSPH approach in terms of its simulation accuracy and efficiency.展开更多
基金Supported by Joint Projects of the Medical Science and Technology Research Program of Henan Province,No.LHGJ20210255.
文摘BACKGROUND Extracorporeal membrane oxygenation(ECMO)is a new type of extracorporeal respiratory and circulatory assistance device.It can drain venous blood out of the body and inject it into veins or arteries after being oxygenated by an oxygenator(membrane lung)to replace lung and heart functions in a short time.ECMO can provide tissue blood perfusion and gas exchange almost equivalent to cardiac output and extend the effective treatment time window for patients with acute circulatory failure to restore cardiopulmonary function.CASE SUMMARY We report a case of an 81-year-old woman who underwent whole cerebral angiography,basilar artery thrombectomy and stent thrombectomy in the posterior artery of the left brain after implantation of ECMO.The patient was admitted to the hospital due to myocardial infarction.Considering that the cause of the patient’s disturbance of consciousness was unknown and cerebrovascular accident could not be ruled out after the implantation of ECMO,the department of Radioactive Intervention performed cerebral angiography.And the result of the angiography indicated vascular occlusion.After the basilar artery thrombectomy and stent thrombectomy in the posterior artery of the left brain,the patency of the occlusive vessel was achieved.CONCLUSION Although the patient eventually died of circulatory failure,the result of this case verifies the feasibility of cerebral angiography and thrombectomy in patients with implanted ECMO in the intubated state.
基金supported by the National Natural Science Foundation of China(Grant No.52201323).
文摘In this study,a common-node DEM-SPH coupling model based on the shared node method is proposed,and a fluid–structure coupling method using the common-node discrete element method-smoothed particle hydrodynamics(DS-SPH)method is developed using LS-DYNA software.The DEM and SPH are established on the same node to create common-node DEM-SPH particles,allowing for fluid–structure interactions.Numerical simulations of various scenarios,including water entry of a rigid sphere,dam-break propagation over wet beds,impact on an ice plate floating on water and ice accumulation on offshore structures,are conducted.The interaction between DS particles and SPH fluid and the crack generation mechanism and expansion characteristics of the ice plate under the interaction of structure and fluid are also studied.The results are compared with available data to verify the proposed coupling method.Notably,the simulation results demonstrated that controlling the cutoff pressure of internal SPH particles could effectively control particle splashing during ice crushing failure.
基金Project supported by the National Natural Science Foundation of China(Nos.11872283 and 2002212)the Sailing Program of Shanghai,China(No.20YF1432800)。
文摘In the present study,the nanofliud natural convection is investigated by the energy-conserving dissipative particle dynamics(eDPD)method,where the nanoparticles are considered at the single-particle level.The thermal expansion coefficientβand the viscosityμof the simulated system containing nanoparticles are calculated and found to be in close alignment with the previous simulation results.The single-particle hydrodynamics in e DPD enables simulations of nanofluid natural convection with higher Rayleigh numbers and greater nanoparticle volume fractions.Additionally,this approach is utilized to simulate the nanoparticle distribution during the enhanced heat transfer process in the nanofluid natural convection.The localized aggregation of nanoparticles enhances the heat transfer performance of the nanofluid under specific Rayleigh numbers and nanoparticles volume fractions.
基金funded by the National Key Research and Development Program of China(Grant No.2023YFC3008300,Grant No.2019YFC1509702)the National Natural Science Foundation of China(Grant No.42172296).
文摘Residual strength is an indispensable factor in evaluating rock fracture,yet the current Smoothed Particle Hydrodynamics(SPH)framework rarely considers its influence when simulating fracture.An improved cracking strategy considering residual stress in the base bond SPH method was proposed to simulate failures in layered rocks and slopes and verified by experimental results and other simulation methods(i.e.,the discrete element method).Modified Mohr–Coulomb failure criterion was applied to distinguish the mixed failure of tensile and shear.Bond fracture markψwas introduced to improve the kernel function after tensile damage,and the calculation of residual stress after the damage was derived after shear damage.Numerical simulations were carried out to evaluate its performance under different stress and scale conditions and to verify its effectiveness in realistically reproducing crack initiation and propagation and coalescence,even fracture and separation.The results indicate that the improved cracking strategy precisely captures the fracture and failure pattern in layered rocks and rock slopes.The residual stress of brittle tock is correctly captured by the improved SPH method.The improved SPH method that considers residual strength shows an approximately 13%improvement in accuracy for the safety factor of anti-dip layered slopes compared to the method that does not consider residual strength,as validated against analytical solutions.We infer that the improved SPH method is effective and shows promise for applications to continuous and discontinuous rock masses.
基金open foundation of the Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanicsthe Open Foundation of Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment.
文摘A fluid-structure interaction approach is proposed in this paper based onNon-Ordinary State-Based Peridynamics(NOSB-PD)and Updated Lagrangian Particle Hydrodynamics(ULPH)to simulate the fluid-structure interaction problem with large geometric deformation and material failure and solve the fluid-structure interaction problem of Newtonian fluid.In the coupled framework,the NOSB-PD theory describes the deformation and fracture of the solid material structure.ULPH is applied to describe the flow of Newtonian fluids due to its advantages in computational accuracy.The framework utilizes the advantages of NOSB-PD theory for solving discontinuous problems and ULPH theory for solving fluid problems,with good computational stability and robustness.A fluidstructure coupling algorithm using pressure as the transmission medium is established to deal with the fluidstructure interface.The dynamic model of solid structure and the PD-ULPH fluid-structure interaction model involving large deformation are verified by numerical simulations.The results agree with the analytical solution,the available experimental data,and other numerical results.Thus,the accuracy and effectiveness of the proposed method in solving the fluid-structure interaction problem are demonstrated.The fluid-structure interactionmodel based on ULPH and NOSB-PD established in this paper provides a new idea for the numerical solution of fluidstructure interaction and a promising approach for engineering design and experimental prediction.
基金the National Natural Science Foundation of China(No.52271316)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515030262).
文摘Predicting the response of liquefied natural gas(LNG)contained in vessels subjected to external waves is extremely important to ensure the safety of the transportation process.In this study,the coupled behavior due to ship motion and liquid tank sloshing has been simulated by the Smoothed-Particle Hydrodynamics(SPH)method.Firstly,the sloshing flow in a rectangular tank was simulated and the related loads were analyzed to verify and validate the accuracy of the present SPH solver.Then,a three-dimensional simplified LNG carrier model,including two prismatic liquid tanks and a wave tank,was introduced.Different conditions were examined corresponding to different wave lengths,wave heights,wave heading angles,and tank loading rates.Finally,the effects of liquid tank loading rate on LNG ship motions and sloshing loading were analyzed,thereby showing that the SPH method can effectively provide useful indications for the design of liquid cargo ships.
基金support from the National Natural Science Foundations of China(Nos.11972267 and 11802214)the Open Foundation of the Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics and the Open Foundation of Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment.
文摘Natural convection is a heat transfer mechanism driven by temperature or density differences,leading to fluid motion without external influence.It occurs in various natural and engineering phenomena,influencing heat transfer,climate,and fluid mixing in industrial processes.This work aims to use the Updated Lagrangian Particle Hydrodynamics(ULPH)theory to address natural convection problems.The Navier-Stokes equation is discretized using second-order nonlocal differential operators,allowing a direct solution of the Laplace operator for temperature in the energy equation.Various numerical simulations,including cases such as natural convection in square cavities and two concentric cylinders,were conducted to validate the reliability of the model.The results demonstrate that the proposed model exhibits excellent accuracy and performance,providing a promising and effective numerical approach for natural convection problems.
文摘The Theory of General Singularity is presented, unifying quantum field theory, general relativity, and the standard model. This theory posits phonons as fundamental excitations in a quantum vacuum, modeled as a Bose-Einstein condensate. Through key equations, the role of phonons as intermediaries between matter, energy, and spacetime geometry is demonstrated. The theory expands Einsteins field equations to differentiate between visible and dark matter, and revises the standard model by incorporating phonons. It addresses dark matter, dark energy, gravity, and phase transitions, while making testable predictions. The theory proposes that singularities, the essence of particles and black holes, are quantum entities ubiquitous in nature, constituting the very essence of elementary particles, seen as micro black holes or quantum fractal structures of spacetime. As the theory is refined with increasing mathematical rigor, it builds upon the foundation of initial physical intuition, connecting the spacetime continuum of general relativity with the hydrodynamics of the quantum vacuum. Inspired by the insights of Tesla and Majorana, who believed that physical intuition justifies the infringement of mathematical rigor in the early stages of theory development, this work aims to advance the understanding of the fundamental laws of the universe and the perception of reality.
基金Project supported by the National Natural Science Foundation of China(No.52109068)the Water Conservancy Technology Project of Jiangsu Province of China(No.2022060)。
文摘Viscoelastic flows play an important role in numerous engineering fields,and the multiscale algorithms for simulating viscoelastic flows have received significant attention in order to deepen our understanding of the nonlinear dynamic behaviors of viscoelastic fluids.However,traditional grid-based multiscale methods are confined to simple viscoelastic flows with short relaxation time,and there is a lack of uniform multiscale scheme available for coupling different solvers in the simulations of viscoelastic fluids.In this paper,a universal multiscale method coupling an improved smoothed particle hydrodynamics(SPH)and multiscale universal interface(MUI)library is presented for viscoelastic flows.The proposed multiscale method builds on an improved SPH method and leverages the MUI library to facilitate the exchange of information among different solvers in the overlapping domain.We test the capability and flexibility of the presented multiscale method to deal with complex viscoelastic flows by solving different multiscale problems of viscoelastic flows.In the first example,the simulation of a viscoelastic Poiseuille flow is carried out by two coupled improved SPH methods with different spatial resolutions.The effects of exchanging different physical quantities on the numerical results in both the upper and lower domains are also investigated as well as the absolute errors in the overlapping domain.In the second example,the complex Wannier flow with different Weissenberg numbers is further simulated by two improved SPH methods and coupling the improved SPH method and the dissipative particle dynamics(DPD)method.The numerical results show that the physical quantities for viscoelastic flows obtained by the presented multiscale method are in consistence with those obtained by a single solver in the overlapping domain.Moreover,transferring different physical quantities has an important effect on the numerical results.
基金funding from the European Union’s Horizon 2020 research and innovation program under Grant Agreement No.871124 Laserlab-Europeby Grant No.ANR-17-CE30-0026-Pinnacle from the Agence Nationale de la Recherche.
文摘We have recently proposed a new technique of plasma tailoring by laser-driven hydrodynamic shockwaves generated on both sides of a gas jet[Marquès et al.,Phys.Plasmas 28,023103(2021)].In a continuation of this numerical work,we study experimentally the influence of the tailoring on proton acceleration driven by a high-intensity picosecond laser in three cases:without tailoring,by tailoring only the entrance side of the picosecond laser,and by tailoring both sides of the gas jet.Without tailoring,the acceleration is transverse to the laser axis,with a low-energy exponential spectrum,produced by Coulomb explosion.When the front side of the gas jet is tailored,a forward acceleration appears,which is significantly enhanced when both the front and back sides of the plasma are tailored.This forward acceleration produces higher-energy protons,with a peaked spectrum,and is in good agreement with the mechanism of collisionless shock acceleration(CSA).The spatiotemporal evolution of the plasma profile is characterized by optical shadowgraphy of a probe beam.The refraction and absorption of this beam are simulated by post-processing 3D hydrodynamic simulations of the plasma tailoring.Comparison with the experimental results allows estimation of the thickness and near-critical density of the plasma slab produced by tailoring both sides of the gas jet.These parameters are in good agreement with those required for CSA.
基金Supported by the National Natural Science Foundation of China(No.31872609)the Innovation Support Program for High-level Talents of Dalian City(No.2019RD12)+1 种基金the Key Research Project of Liaoning Provincial Department of Education in 2022(No.LJKZZ 20220091)the earmarked fund for CARS-49(CARS-49)。
文摘To adapt to the change of aquaculture workshop site,optimize the shape of aquaculture tanks and improve the utilization rate of breeding space,it is necessary to determine the appropriate length width ratio parameters of aquaculture tanks.In this paper,computational fluid dynamics(CFD)technology is adopted to study the flow field performance of aquaculture tanks with different L/B ratios(L:the length;B:the width,of aquaculture tank)and different jet direction conditions(lengthways jet and widthways jet).A three-dimensional numerical calculation model of turbulence in rounded rectangle aquaculture tanks in dual-diagonal-inlet layout was established.Jet directions are arranged lengthways and widthways,and the water flow velocity,resistance coefficient change,vorticity,etc.are analyzed under two working conditions.Results show that the flow field performance in aquaculture tank decreases with the increase of the L/B ratio.The flow field performed well when L/B was 1.0-1.3,sharply dropped at 1.4-1.6,and poor at 1.7-1.9.The results provided a theoretical basis for the design and optimization in flow field performance of the industrialized circulating aquaculture tanks.
基金financially supported by China National Funds for Distinguished Young Scientists(Grant No.52025112)the Key Projects of the National Natural Science Foundation of China(Grant No.52331011)。
文摘Two-dimensional(2D)flume experiments are useful in investigating the performances of floating breakwaters(FBs),including hydrodynamic performances,motion responses,and mooring forces.Designing a reasonable gap between the flume wall and the FBs is a critical step in 2D flume tests.However,research on the effect of the gap on the accuracy of 2D FB experimental results is scarce.To address this issue,a numerical wave tank is developed using CFD to estimate the wave-FB interaction of a moored dual-cylindrical FB,and the results are compared to experimental data from a previously published work.There is good agreement between them,indicating that the numerical model is sufficiently accurate.The numerical model is then applied to explore the effect of gap diffraction on the performance of FBs in2D experiments.It was discovered that the nondimensional gap length L_(Gap)/W_(Pool)should be smaller than 7.5%to ensure that the relative error of the transmission coefficient is smaller than 3%.The influence of the gap is also related to the entering wave properties,such as the wave height and period.
基金supported by the Key Research and Development Plan of Shandong Province(the Major Scientific and Technological Innovation Projects,2021ZDSYS13)the Natural Science Foundation of Shandong Province(ZR2021MB135)Natural Science Foundation of Shandong Province(ZR2021ME224).
文摘It is of vital significance to investigate mass transfer enhancements for chemical engineering processes.This work focuses on investigating the coupling influence of embedding wire mesh and adding solid particles on bubble motion and gas-liquid mass transfer process in a bubble column.Particle image velocimetry(PIV)technology was employed to analyze the flow field and bubble motion behavior,and dynamic oxygen absorption technology was used to measure the gas-liquid volumetric mass transfer coefficient(kLa).The effect of embedding wire mesh,adding solid particles,and wire mesh coupling solid particles on the flow characteristic and kLa were analyzed and compared.The results show that the gas-liquid interface area increases by 33%-72%when using the wire mesh coupling solid particles strategy compared to the gas-liquid two-phase flow,which is superior to the other two strengthening methods.Compared with the system without reinforcement,kLa in the bubble column increased by 0.5-1.8 times with wire mesh coupling solid particles method,which is higher than the sum of kLa increases with inserting wire mesh and adding particles,and the coupling reinforcement mechanism for affecting gas-liquid mass transfer process was discussed to provide a new idea for enhancing gas-liquid mass transfer.
基金supported by the National Key R&D Plan(No.2023YFD2401104)Tianjin Agricultural Development Service Center Science and Technology Innovation Project for Youth(No.ZXKJ202429 and No.ZXKJ202454).
文摘Artificial fish reef is a kind of artificial structure in water,which provides a necessary and safe place for aquatic life such as fish to inhabit,grow,and breed,and creates an environment suitable for fish growth,so as to protect and multiply fishery resources.In a large time scale,the physical process of sea area can deeply affect the chemical process and biological process,so the structure characteristics of artificial reef are the key factors affecting the flow field effect around the reef.In this study,through the hydrodynamic experiments of four kinds of reef models,including big windows box reef,big and small windows box reef,"(卐)"shaped reef and double-layer shellfish breeding reef,the influence of single reef structure on the flow field effect is analyzed,and the force conditions of different reefs under the same incoming current velocity are obtained.According to the simulation results,the safety research and calculation of five kinds of reef models are carried out,and the volumes of vortex area and upwelling area behind four kinds of reef are obtained.Using hydrodynamic model to simulate the flow field effect of reef area,optimizing the reef structure design,improving the maximum biological trapping and proliferation effect of reef,can provide theoretical guidance and scientific and technological support for the construction of reef area.
基金Supported by Beijing Municipal Administration of Hospital Incubating Program,No,PX2022015。
文摘BACKGROUND The inferior vena cava filter is utilized worldwide to intercept thrombi and to reduce the risk of fatal pulmonary embolism(PE).However,filter-related thrombosis is a complication of filter implantation.Endovascular methods such as AngioJet rheolytic thrombectomy(ART)and catheter-directed thrombolysis(CDT)can treat filter-related caval thrombosis,but the clinical outcomes of both treatment modalities have not been determined.AIM To compare the treatment outcomes of AngioJet rheolytic thrombectomy vs catheter-directed thrombolysis in patients with filter-related caval thrombosis.METHODS In this single-center retrospective study,65 patients(34 males and 31 females;mean age:59.0±13.43 years)with intrafilter and inferior vena cava thrombosis were enrolled between January 2021 and August 2022.These patients were assigned to either the AngioJet group(n=44)or the CDT group(n=21).Clinical data and imaging information were collected.Evaluation measures included thrombus clearance rate,periprocedural complications,urokinase dosage,incidence of PE,limb circumference difference,length of stay,and filter removal rate.RESULTS Technical success rates were 100%in the AngioJet and CDT groups.In the AngioJet group,grade II and grade III thrombus clearance was achieved in 26(59.09%)and 14(31.82%)patients,respectively.In the CDT group,grade II and grade III thrombus clearance was accomplished in 11(52.38%)patients and 8(38.10%)patients,respectively(P>0.05).The peridiameter difference of the thigh was significantly reduced in patients from both groups after treatment(P<0.05).The median dosage of urokinase was 0.08(0.02,0.25)million U in the AngioJet group and 1.50(1.17,1.83)million U in the CDT group(P<0.05).Minor bleeding was shown in 4(19.05%)patients in the CDT group,and when it was compared with that in the AngioJet group,the difference was statistically significant(P<0.05).No major bleeding occurred.Seven(15.91%)patients in the AngioJet group had hemoglobinuria and 1(4.76%)patient in the CDT group had bacteremia.There were 8(18.18%)patients with PE in the AngioJet group and 4(19.05%)patients in the CDT group before the intervention(P>0.05).Computed tomography angiopulmonography(CTA)showed that PE was resolved after the intervention.New PE occurred in 4(9.09%)patients in the AngioJet group and in 2(9.52%)patients in the CDT group after theintervention(P>0.05).These cases of PE were asymptomatic.The mean length of stay was longer in the CDT group(11.67±5.34 d)than in the AngioJet group(10.64±3.52 d)(P<0.05).The filter was successfully retrieved in the first phase in 10(47.62%)patients in the CDT group and in 15(34.09%)patients in the AngioJet group(P>0.05).Cumulative removal was accomplished in 17(80.95%)out of 21 patients in the CDT group and in 42(95.45%)out of 44 patients in the ART group(P>0.05).The median indwelling time for patients with successful retrieval was 16(13139)d in the CDT group and 59(12231)d in the ART group(P>0.05).CONCLUSION Compared with catheter-directed thrombolysis,AngioJet rheolytic thrombectomy can achieve similar thrombus clearance effects,improve the filter retrieval rate,reduce the urokinase dosage and lower the risk of bleeding events in patients with filter-related caval thrombosis.
基金supported by the Medical and Health Science and Technology Development Plan of Shandong Province, China (Grant No.2017WS688)。
文摘Objective: To evaluate the risk factors for hemoglobinuria and acute kidney injury(AKI) after percutaneous mechanical thrombectomy(MT) with or without catheter-directed thrombolysis(CDT) for iliofemoral deep vein thrombosis(IFDVT).Methods: Patients with IFDVT who had MT with the Angio Jet catheter(group A), MT plus CDT(group B), or CDT alone(group C) from January 2016 to March 2020 were retrospectively evaluated. Hemoglobinuria was monitored throughout the treatment course, and postoperative AKI was assessed by comparing the preoperative(baseline) and postoperative serum creatinine(sCr) levels from the electronic medical records of all patients. AKI was defined as an elevation in the sCr level exceeding 26.5 μmol/L within 72 h after the operation according to the Kidney Disease Improving Global Outcomes criteria.Results: A total of 493 consecutive patients with IFDVT were reviewed, of which 382(mean age, 56 ± 11 years;41% of them were females;97 in group A, 128 in group B, and 157 in group C) were finally analyzed. Macroscopic hemoglobinuria was evident in 44.89% of the patients of the MT groups(101/225, 39 in group A, and 62 in group B), with no significant difference between the groups(P = 0.219), but not in the patients in group C. None of the patients developed AKI(mean sCr difference-2.76 ± 13.80 μmol/L, range =-80.20 to 20.60 μmol/L) within 72h after surgery.Conclusions: Rheolytic MT is an independent risk factor for hemoglobinuria. A proper aspiration strategy, hydration, and alkalization following thrombectomy are particularly favorable for preventing AKI.
文摘BACKGROUND A carotid-cavernous fistula(CCF)is an abnormal connection between the internal carotid artery(ICA)and the cavernous sinus.Although direct CCFs typically result from trauma or as an iatrogenic complication of neuroendovascular procedures,they can occur as surgery-related complications after mechanical thrombectomy(MT).With the widespread use of MT in patients with acute ischemic stroke complicated with large vessel occlusion,it is important to document CCF following MT and how to avoid them.In this study,we present a case of a patient who developed a CCF following MT and describe in detail the characteristics of ICA tortuosity in this case.CASE SUMMARY A 60-year-old woman experienced weakness in the left upper and lower limbs as well as difficulty speaking for 4 h.The neurological examination revealed left central facial paralysis and left hemiplegia,with a National Institutes of Health Stroke Scale score of 9.Head magnetic resonance imaging revealed an acute cerebral infarction in the right basal ganglia and radial crown.Magnetic resonance angiography demonstrated an occlusion of the right ICA and middle cerebral artery.Digital subtraction angiography demonstrated distal occlusion of the cervical segment of the right ICA.We performed suction combined with stent thrombectomy.Then,postoperative angiography was performed,which showed a right CCF.One month later,CCF embolization was performed,and the patient’s clinical symptoms have significantly improved 5 mo after the operation.CONCLUSION Although a CCF is a rare complication after MT,it should be considered.Understanding the tortuosity of the internal carotid-cavernous sinus may help predict the complexity of MT and avoid this complication.
文摘Flow-type landslide is one type of landslide that generally exhibits characteristics of high flow velocities,long jump distances,and poor predictability.Simulation of its propagation process can provide solutions for risk assessment and mitigation design.The smoothed particle hydrodynamics(SPH)method has been successfully applied to the simulation of two-dimensional(2D)and three-dimensional(3D)flow-like landslides.However,the influence of boundary resistance on the whole process of landslide failure is rarely discussed.In this study,a boundary condition considering friction is proposed and integrated into the SPH method,and its accuracy is verified.Moreover,the Navier-Stokes equation combined with the non-Newtonian fluid rheologymodel was utilized to solve the dynamic behavior of the flow-like landslide.To verify its performance,the Shuicheng landslide event,which occurred in Guizhou,China,was taken as a case study.In the 2D simulation,a sensitivity analysis was conducted,and the results showed that the shearing strength parameters have more influence on the computation accuracy than the coefficient of viscosity.Afterwards,the dynamic characteristics of the landslide,such as the velocity and the impact area,were analyzed in the 3D simulation.The simulation results are in good agreement with the field investigations.The simulation results demonstrate that the SPH method performs well in reproducing the landslide process,and facilitates the analysis of landslide characteristics as well as the affected areas,which provides a scientific basis for conducting the risk assessment and disaster mitigation design.
基金High Level Talent Program of Hainan Natural Science Foundation(No.821RC680)。
文摘Acute ischemic stroke is one of the common discases in Chinese,among which acute ischemic stroke with large vessel occlusion(AIS-LVO)has thc most serious complications and has the risk of death.Studies have shown that reperfusion is a first-line treatment for the effective rescue of ischemic brain tissue,usually mainly by mechanical|hrombectomy(MT),supplemented by intravenous thrombolysis.However,there are still complications after large blood vessel occlusion and MT.such as blecding and infection at the puncture point,vasospasm,vascular dissection,subarachnoid hemorrhage,hcmonhagic transfomation,reembolization,and massive cerebral infarction,ctc.The high risk factors and corresponding measures of complications after MT by revicwing the rescarch analysis.
基金the Key Program of National Natural Science Foundation of China,No.62237001National Natural Science Foundation for Excellent Young Scholars,No.6212200101+2 种基金National Natural Science Foundation for General Program,Nos.62176066 and 61976052Guangdong Provincial Science and Technology Innovation Strategy Fund,No.2019B121203012and Guangzhou Science and Technology Plan,No.202007040005.
文摘In classical smoothed particle hydrodynamics(SPH)fluid simulation approaches,the smoothing length of Lagrangian particles is typically constant.One major disadvantage is the lack of adaptiveness,which may compromise accuracy in fluid regions such as splashes and surfaces.Attempts to address this problem used variable smoothing lengths.Yet the existing methods are computationally complex and non-efficient,because the smoothing length is typically calculated using iterative optimization.Here,we propose an efficient non-iterative SPH fluid simulation method with variable smoothing length(VSLSPH).VSLSPH correlates the smoothing length to the density change,and adaptively adjusts the smoothing length of particles with high accuracy and low computational cost,enabling large time steps.Our experimental results demonstrate the advantages of the VSLSPH approach in terms of its simulation accuracy and efficiency.